<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8" />
	<title>JavaScript</title>
	<style>
		body{background:#66ccff;}
	</style>
	<script type="text/javascript">
	
	</script>
</head>
<body>
	<!--需要注意的是，这个js只能放在body里。-->
	<!--下面的是具体代码。-->
	<!--count  ：线条数量。zindex ：层级。opacity：透明度。color   ：线条颜色。最好用RGB颜色。-->
	<script src="http://open.sojson.com/common/js/canvas-nest.min.js" count="200" zindex="-2" opacity="0.5" color="47,135,193" type="text/javascript">
		! function() {
		//封装方法，压缩之后减少文件大小
		function get_attribute(node, attr, default_value) {
			return node.getAttribute(attr) || default_value;
		}
		//封装方法，压缩之后减少文件大小
		function get_by_tagname(name) {
			return document.getElementsByTagName(name);
		}
		//获取配置参数
		function get_config_option() {
			var scripts = get_by_tagname("script"),
				script_len = scripts.length,
				script = scripts[script_len - 1]; //当前加载的script
			return {
				l: script_len, //长度，用于生成id用
				z: get_attribute(script, "zIndex", -1), //z-index
				o: get_attribute(script, "opacity", 0.5), //opacity
				c: get_attribute(script, "color", "0,0,0"), //color
				n: get_attribute(script, "count", 99) //count
			};
		}
		//设置canvas的高宽
		function set_canvas_size() {
			canvas_width = the_canvas.width = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth, 
			canvas_height = the_canvas.height = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight;
		}
		//绘制过程
		function draw_canvas() {
			context.clearRect(0, 0, canvas_width, canvas_height);
			//随机的线条和当前位置联合数组
			var all_array = [current_point].concat(random_lines);
			var e, i, d, x_dist, y_dist, dist; //临时节点
			//遍历处理每一个点
			random_lines.forEach(function(r) {
				r.x += r.xa, 
				r.y += r.ya, //移动
				r.xa *= r.x > canvas_width || r.x < 0 ? -1 : 1, 
				r.ya *= r.y > canvas_height || r.y < 0 ? -1 : 1, //碰到边界，反向反弹
				context.fillRect(r.x - 0.5, r.y - 0.5, 1, 1); //绘制一个宽高为1的点
				for (i = 0; i < all_array.length; i++) {
					e = all_array[i];
					//不是当前点
					if (r !== e && null !== e.x && null !== e.y) {
							x_dist = r.x - e.x, //x轴距离 l
							y_dist = r.y - e.y, //y轴距离 n
							dist = x_dist * x_dist + y_dist * y_dist; //总距离, m
						dist < e.max && (e === current_point && dist >= e.max / 2 && (r.x -= 0.03 * x_dist, r.y -= 0.03 * y_dist), //靠近的时候加速
							d = (e.max - dist) / e.max, 
							context.beginPath(), 
							context.lineWidth = d / 2, 
							context.strokeStyle = "rgba(" + config.c + "," + (d + 0.2) + ")", 
							context.moveTo(r.x, r.y), 
							context.lineTo(e.x, e.y), 
							context.stroke());
					}
				}
				all_array.splice(all_array.indexOf(r), 1);
			}), frame_func(draw_canvas);
		}
		//创建画布，并添加到body中
		var the_canvas = document.createElement("canvas"), //画布
			config = get_config_option(), //配置
			canvas_id = "c_n" + config.l, //canvas id
			context = the_canvas.getContext("2d"), canvas_width, canvas_height, 
			frame_func = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function(func) {
				window.setTimeout(func, 1000 / 45);
			}, random = Math.random, 
			current_point = {
				x: null, //当前鼠标x
				y: null, //当前鼠标y
				max: 20000
			};
		the_canvas.id = canvas_id;
		the_canvas.style.cssText = "position:fixed;top:0;left:0;z-index:" + config.z + ";opacity:" + config.o;
		get_by_tagname("body")[0].appendChild(the_canvas);
		//初始化画布大小
		set_canvas_size(), window.onresize = set_canvas_size;
		//当时鼠标位置存储，离开的时候，释放当前位置信息
		window.onmousemove = function(e) {
			e = e || window.event, current_point.x = e.clientX, current_point.y = e.clientY;
		}, window.onmouseout = function() {
			current_point.x = null, current_point.y = null;
		};
		//随机生成config.n条线位置信息
		for (var random_lines = [], i = 0; config.n > i; i++) {
			var x = random() * canvas_width, //随机位置
				y = random() * canvas_height,
				xa = 2 * random() - 1, //随机运动方向
				ya = 2 * random() - 1;
			random_lines.push({
				x: x,
				y: y,
				xa: xa,
				ya: ya,
				max: 6000 //沾附距离
			});
		}
		//0.1秒后绘制
		setTimeout(function() {
			draw_canvas();
		}, 100);
		}();
	</script>
</body>
</html>
